Generally, automotive vehicles (hereinafter referred to simply as “vehicles”) have, in their rear side surface, a filling port for supplying fuel into the vehicle. In some automotive vehicles, a direction regulating member is provided inside the interior of the filling port for regulating a flow direction of the fuel emitted from a fuel filling gun (see, for example, Japanese Patent Publication No. 3,578,421, which will hereinafter be referred to as “Patent Document 1”). Further, in some vehicles, a position regulating structure is provided inside the filling port for regulating an inserted position of the fuel filling gun (see, for example, Japanese Patent Publication No. 3,616,516, which will hereinafter be referred to as “Patent Document 2”). Also known are vehicles where a fuel filler tube is constructed as a dual-tube structure (see, for example, Japanese Patent Application Laid-Open Publication No. 2003-252069, which will hereinafter be referred to as “Patent Document 3”.
FIG. 9 hereof illustrates a fuel filler tube structure 201 disclosed in Patent Document 1. The fuel filler tube structure 201 includes a flow direction regulating member 204 of a substantially U cross-sectional shape provided near a filling port 203 of a fuel filler tube 202, and the flow direction regulating member 204 has a flow guide surface slants with respect to the axis line of the fuel filler tube 202 in an upward/downward direction and leftward/rightward direction such that fuel is guided to a fuel tank while swirling spirally along the inner surface of the fuel filler tube 202; thus, undesired scattering of the fuel within the fuel filler tube 202 can be prevented, so that an amount of evaporation of the fuel can be minimized.
However, when a filling nozzle in the filling port 203 is not inserted in the filling port 203 to a sufficient degree, a considerable portion of the fuel emitted from the distal end of the filling nozzle flows down through a free space over the flow direction regulating member 204 without being appropriately guided by the flow direction regulating member 204, and thus, there can be achieved only a weak flow force of the fuel. Particularly, in applications where the filling port 203 needs to be oriented vertically, the flow direction regulating member 204 also extends vertically, and thus, the fuel tends to easily flows down the flow direction regulating member 204 without being appropriately guided by the regulating member 204, so that the flowing speed of the fuel would undesirably decrease.
FIG. 10 is a view of explanatory of a fuel filler tube structure disclosed in Patent Document 2, in which a nozzle-inserted-position regulating structure 231 includes a position regulating member 234 provided on an inner wall surface 233 of a filler tube 232 and having an abutting portion 235. Nozzle 237 of a fuel filling gun 237 abuts against the abutting portion 235, so that the inserted position of the nozzle 237 can be appropriately regulated.
The nozzle-insertion regulating structure 231 can regulate a maximum inserted position of the fuel filling gun 236 as desired, but, even when the fuel filling gun 236 is not inserted to the maximum inserted position, i.e. even when the nozzle 237 is inserted halfway into the filler tube 232, fueling is permitted because a (coil) spring 238 of the nozzle 237 is engaged by a threaded portion 239 of a filler neck of the filler tube 232. The fuel emitted from the insufficiently-inserted nozzle 237 would undesirably jet out scatteringly toward the inner wall surface 233 of the filler tube 232, so that the fuel can not flow through the tube 232 easily and smoothly.
FIG. 11 is a view of explanatory of a fuel filler tube structure 261 disclosed in Patent Document 3. In the fuel filler tube structure 261, a fuel filler tube 263, leading to a fuel tank 262, is constructed as a dual-tube structure including a small-diameter tube 265 substantially equal in diameter to a fuel filling gun 264 and a large-diameter tube 267 surrounding the small-diameter tube 265 with a gap that functions as an overflow path 266 for fuel overflown from the small-diameter tube 265. With such an overflow path 266, the fuel filler tube 261 permits smooth fueling.
However, the fuel filler tube 261 is complicated in construction because the small-diameter tube 265 needs to be provided within the large-diameter tube 267. Particularly, in a case where the fuel filler tube 263 has a great length and many bent portions, the construction of the fuel filler tube structure 261 would become very complicated.